Toggle clamp



March 1967 J. J- SENDOYKAS 3,311,367

TOGGLE CLAMP Filed Nov. 12, 1964 4 Sheets-Sheet 2 March 28 3967 J. J. SENDOYKAS TOGGLE CLAMP Filed Nov. 12, 1964 4 Sheets-Sheet 4 United States Patent 3,311,367 TOGGLE CLAMP Jack J. Sendoykas, 3201 E. Jefferson Ave., Apt. 1, St. Clair Shores, Mich. 48682 Filed Nov. 12, 1964, Ser. No. 410,519 21 Claims. (Cl. 26991) This invention relates to clamping means for holding a workpiece and to a new and improved clamp actuating mechanism.

It is common practice to hold a workpiece by one or more clamps for a machining, forming or other operation. These clamps, of course, must hold the workpiece with considerable pressure as tthe operation frequently exerts great force on the work. Also, the clamps must be quickly engageable with and releasable from the work so as not to interfere with or to extend the normal cycle of the machine or other equipment with which they are associated. The clamp of this invention satisfies these requirements.

It frequently happens, too, that the work must be placed in a confined space which provides limited clearance overhead or behind the clamps; and in some situations it is necessary to move the workpiece into place over the clamps. There is a need in the art, therefore, for a quickly engageable and releasable clamp that can operate under conditions where the overhead and rear clearances are at a minimum and which drops the clamping arm and other operating parts down out of the way when released. T he clamp of this invention is uniquely formed and constructed also to satisfy this requirement.

In addition, the clamp of this invention is uniquely constructed so that most if not all of the operating parts can be made by inexpensive stamping and forming operations. None of the parts need be held to such close tolerances that manufacturing costs are excessive, and all of the parts can be assembled relatively easily and quickly to minimize the time and cost of fabrication. Further, the moving parts of the clamp assembly seat solidly against fixed locking surfaces or abutments to hold and lock the parts positively in clamping position until released.

In general, the invention comprises a clamp having work clamping means movable between a closed or work clamping position and a released or open position. Actuator means preferably in the form of a manually operable handle are provided to actuate the work clamping means between the open and closed positions. Support link means pivotally support the work clamping means; and the support link means and the handle are pivotally connected to a fixedly mounted base by a common pivot. Control link means are ivotally connected to the handle and to the work clamping means, and have abutment portions adapted to abuttingly engage the work clamping means during movement to and in the closed position and during movement to and in the open position. In addition, roller means provided at the pivot connections between both of the link means and the work clamping means travel on a cam surface on the base to guide the movement of the operating parts between the open and the closed positions. Stop means are provided for seating and locking the operating parts in the closed position.

The inventive principles and concepts are hereinafter described in detail by refernce to an illustrative embodiment as shown on the accompanying drawings in which:

FIGURE 1 is a side elevational view of a form of the invention adapted particularly for mounting on a hori- Patented Mar. 28, I957 zontal surface and showing the operating parts thereof in closed position;

FIG. 2 is a top plan view of the same;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a fragmentary, horizontal sectional view taken on the line 44 in FIG. .1;

FIG. 5 is a fragmentary, transverse sectional view taken on the line 55 in FIG. 1;

FIG. 6 is a fragmentary, vertical sectional view taken on the line 6-6 in FIG. 1;

FIG. 7 is a side elevational view of the clamp showing the operating parts thereof in an intermediate operational position;

FIG. 8 is a view similar to FIG. 7 but showing the operating parts in a fully open position;

FIG. 9 is a side elevational view of a modified form of the invention adapted for mounting on a vertical surface and showing the operating parts in an intermediate operational position; and

FIG. 10 is a view similar to FIG. 9 but showing the operating parts in fully open position.

Referring now to FIG. 1, the illustrative embodiment of the invention is shown to comprise base means 10 fixedly secured to a suitable support 11 and movably supporting work clamping means 12 adapted to engage a workpiece 13. An actuator 14 is pivotally connected to the base means at 15 and is pivotally connected at 17 to one end of control link means to. The other end of control link means 1&5 is pivotally connected at 13 to the work clamping means 12 and a roller 19 is mounted for rotation on the pivot which forms the connection 18. One end of a toggle-type support link means 22 also is pivotally mounted at 15 to the base means 10, and the other end thereof is pivotally connected to the rearward end of work clamping means 12. A roller 21 forming a part of the support link means is mounted for rotation on the pivot which forms the connection 235. In use, in the particular form of the invention shown, both of the rollers 19 and 21 ride on a cam face 20 provided on the base 10.

As seen in FIG. 2, the particular work clamping means 12 here shown comprises a pair of laterally spaced parallel bars 26, 28. In practice the bars 26 and 28 can be of any desired length according to the exi encies of the particular situation, and the user frequently welds or otherwise fastens a suitable adapter block (not shown) or an adjustable clamping screw (also not shown) on the forward or outer ends of the bars for contact with the Work 13. Manifestly, the actual size and shape of the adapter and of the type of adjusting screw (if provided) varies widely depending on the kind and shape of workpiece to be clamped. Sometimes, the manufacturer of the clamp merely provides stub bars 26 and Z8 and the purchaser user welds extensions of suitable length on thebars and equips the extensions with whatever appurtenances are required to adapt the clamp for the particular job at hand. I-Iowever, plain bars 26 and 28 and a single workpiece of block form are here shown by way of example.

The support link means 22. comprise a pair of laterally spaced parallel links 30, 32 disposed at opposite sides of the base 16 and at the outer sides of the work clamping means 12. A pivot pin 33 extends through the overlapping ends of the bars 26, 28 and links 30, 32 to form the pivot connection 23 and the roller 21 is mounted on the pin 33 between the bars to hold the latter suitably spaced apart. A pivot pin 36 extending transversely through the base and through the lower ends of the links 30, 32 and of the actuator 14 provides a common pivot mounting for the links and the actuator.

The base means is here shown in the form of a casting having a flat base mounting portion 38 which is adapted for attachment to the horizontal surface 11 by bolts 39 or the like. Above the mounting portion 38, the base 16 is formed with front and rear longitudinal flange portions 49 and 41 respectively and transverse or laterally extending side flange portions 4-2 and 44-. The upper portions of the side flange 42, 44 are thickened and inclined angularly upwardly and rearwardly to provide a central body portion 46 having parallel sides 48 and 4-9 (FIG. 3) which provide bearing surfaces for the links 30, 32. Opposed laterally outwardly extending lug portions 50 and 51 on the body 46 above the pivot connection provide stop means surfaces 52 and 54 which are adapted to seat the support links 3%), 32 as shown in FIG. 5 and thus lock them in position when the clamp is closed as shown in FIG. 1.

The work clamping means 12 is guided in its travel between open and closed positions by the rollers 19 and 21 which ride on the cam face 20. As shown in the drawings, the entire lower portion of the cam face is generated on an arc about the pivot connection 15 as a center so that both rollers 19 and 21 are in contact with the cam face as the operating parts of the clamp swing from the fully opened position shown in FIG. 8 to a position approaching the fully closed position shown in FIG. 7. In the latter position of the parts, the front roller 19 rolls off of the arcuate cam portion 20 and onto a forwardly facing abutment means 55 which forms an extension of and merges smoothly with the arcuate surface 29 at the forward end thereof. During the final increment of motion of the work clamping means12 to the fully closed position shown in FIG. 1, the front roller 19 moves downwardly on the abutment 55 and, when the clamp is fully closed, the roller 19 remains on the abutment 55 to prevent the work clamping means from moving to the rear and to hold the support link means 22 seated on the stop surfaces 52 and 54. At this time, the rear roller 21 is seated solidly on the arcuate portion 20 to resist any force occurring in use tending to lift the working clamping means 12 off of the work 13. Shoulders 56 and 57 formed by the top surfaces of the body portion 46 at opposite sides and below the abutment 55 limit downward movement of the work clarnp ing means 12. Guide surfaces 58 and 59 formed by the sides of the abutment 55 slidably engage the inner surfaces of the bars and 28 to guide the work clamping means 12 to the closed position.

The actuator 14 here shown is intended for manual operation and comprises a T-shaped upper handle portion 66 mounted on spaced depending leg portions 62 and 64 which extend downwardly in embracing relation to the bars 26 and 28. At the lower ends thereof, the leg portions 62 and as are pivoted on the pin 36 so that the actuator and the support link means 22 turn on a common pivot. This is an important feature of the instant clamp design as it affects the holding action for the work clamping means 12, causes it to retract in a flat are which permits low overhead clearances and drops it quickly to the fully retracted position which permits the clamp to function where the rear clearances are restricted. The central portions 65 and 66 of the legs 62 and 64 are arched outwardly to provide sufficient clearance at the sides of the base 19 and the bars 26 and 28. Areas of the leg portions 62 and 64 adjacent the pivotal connections 15 and 17 bear at 68 and (-9 on and are supported by support link means 22 and on the control link means 16 respectively.

The control link means 16 is disposed between the leg portions 62 and 64 of actuator 14 its upper end being journaled on the pivot 17 and its lower end being journaled on the pivot 18. In form, it is generally channel shaped as perhaps best shown in FIG. 2 having flange portions 72 and 74 interconnected by a forward web portion 76. The latter is relatively short and set forwardly of the main body of the link means 16 so that the bottom edge 78 thereof provides a stop which seats downwardly on the bars 26 and 28 when the clamp is closed as shown in FIG. 1. Rearwardly projecting lugs 89 and 81 (FIG. 2) on the flanges 72 and 74 respectively extend behind the handle when the latter is closed and are inwardly offset as shown in FIG. 2 to overlie the clamping bars 26 and 28. When the clamp is opened, the lugs 80 and 81 engage the rearward ends of the work clamping means approximately at the pivot connection 23 (FIG. 7) and, under the influence of the actuator 14, positively drives or moves the operating parts of the clamp to the fully open position (FIG. 8).

Although the center line 85 shows the pivot connections 15, 17 and 18 in-line, it is preferred that the end pivots 15 and 17 be at least slightly over center with respect to the middle pivot 18 when the clamp is in the fully closed position shown in FIG. 1. Also, in this position of the clamp, a line 86 through the centers of pivot connections 15 and 23 intersects the line 85 at an acute angle of approximately and a line 92 through the centers of pivot connections 18 and 23 is at right angles to the line 85.

It is a feature of the invention that the two rollers 19 and 21 ride on and remain constantly in engagement with the cam face 20 at all times to guide and to control by positive means the movement and action of the operating parts as they move between the opened and closed positions. During the major portion of this movement, the rollers 19 and 21 travel on the arcuate portion of the cam face 29 as shown in'FIGS. 7 and 8, for example, and the arc of the cam face extends below the main supporting pivot 15 so that the operating parts drop well down when the clamp is fully open. Manifestly, the relationship between the arcuate portion of the cam face 26 particularly at the lower end thereof and the pivot connection 15 is an important factor affecting the overhead clearances provided by the fully opened clamp. As suggested, this is important particularly in any situation where it is necessary to insert or remove a part over the clamp.

Of significance also is the fact that both the handle actuator 14 and the support link means 22 are connected to the base 10 through a common pivot 15 which is disposed well forward on the base and at the center of the arcuate cam face portion 20. This relationship between the parts referred to in combination with the action of the supporting rollers 19 and 21 causes the work clamping means 12 to move horizontally in a fiat are which requires minimal overhead clearances in operation. In addition, the forward position of the main supporting pivot 15 on the base 10 minimizes the length of the handle actuator 14 that extends behind the base when the clamp is fully open and consequently minimizes the rearward clearances that must be provided for the operation of the clamp.

The particular relationships described between operating parts of the clamp are important also in holding and positively locking the parts in the closed or clamped position and in maintaining maximum holding and clamping pressure on the work. As the parts move from the partly closed position shown in FIG. 7 to the fully closed position shown in FIG. 1, the front roller 19 runs off of the arcuate portion of the cam face 20 and onto the abutment portion which then backs up and solidly seats the roller 19 to prevent rearward axial movement of the work clamping means 12. Forces tending to so move the work clamping means 12 sometimes occur as a result of a machining operation performed on the workpiece 13.

It is significant also that the rear roller 21 remains in contact with the arcuate cam face portion 20 when the front roller 19 is seated on the abutment 55 so that the two rollers still cooperate to support and steady the work clamping means 12. when the clamp is fully closed. At about the time the front roller 19 moves onto the abutment 55 and the work clamping means 12 begins to drop rapidly onto the workpiece 13, the support link means 22 seats forwardly against the shoulders 52 and 54 to prevent the operating parts of the clamp from there after shifting or rocking bodily forwardly on the supporting pivot 15. Thus, all of the operating parts are solidly seated and held when the clamp is closed.

From the foregoing, it is apparent that the control link means 16 forms a toggle which straightens out as the work clamping ar 12 engages the work. This action, of course, exerts tremendous downward pressure on the clamping bar 12 and holds it solidly against the workpiece 13. This downward pressure, of course, also is applied to the rear roller 21 which merely seats more solidly on the arcuate cam face 29 and thereafter assists in maintaining the forward end of the bar 12 in clamping engagement with the work.

A slight clearance preferably is provided between the work clamping means 12 and the shoulders or seats 56 and 57. However, this clearance should be slight so that the shoulders seat and positively support the work clamping bar 12 in case the vertical tolerance dimension of the work 13 is excessively over size. The downward force exerted by the toggle action of the control link means 16 as the clamp closes is taken up partly by deflection of the support means 22, and the shoulder-stops 56 and 57 prevent excessive deflection of the support link means under these conditions. As suggested, the two end pivots and 17 move slightly over center with respect to the middle pivot 18- when the clamp is fully closed to lock the bar 12 down on the workpiece 13 and the web 76 of the control link means 16 seats downwardly on the clamping bar 12 to limit forward or over center movement of the handle actuator 14. Contran'wise, the lug portions 86 and 81 of the control link means 16 pick up the work clamping bar 12 and the support link means 22 as the clamp is opened and moves the parts positively to the position shown in FIG. 8.

Reference is now had to FIGS. 9 and 10 which show a modified form of the clamp adapted particularly for mounting on a vertical supporting surface 94. This form of the invention is identical to the form first described except that it has a modified base 96. As shown in the drawings, the base 96 has vertical mounting flanges 98 which seat on the vertical supporting surface 94 and are adapted for attachment thereto by bolts 10% or the like. The rest of the clamp and the action of the operation parts is identical to the form of the invention first described with the exception that the rear roller 21 moves off of the arcuate cam face portion in the fully opened position of the clamp shown in FIG. 10. This in turn permits the handie actuator 1-4- to drop all the way down and causes the work clamping bar 12 to drop down to the position shown in FIG. 10. Greater clearances are reuired behind the clamp as a result of this action, but this feature is important particularly in situations where the rear clearances are adequate and the work must be moved into and out of position over the clamp under conditions affording limited overhead clearance.

The invention claimed is:

1. A clamp comprising work engaging means movable between an open retracted position and a closed clamping position, base means movably supporting said work engaging means for movement between the open position and the closed position, support link means pivotally connected to said base means and said work engaging means, cam means provided on said base means, handle means pivotally connected at one end to said support link means and to said base means, control link means pivotally mounted on said handle means and on said work engaging means, first abutment means formed on said control link means and being engageable with said work engaging means in the closed position and during movement to the closed position, second abutment means formed on said control link means and being engageable with said work engaging means in the open position and during movement to the open position, and roller means supporting said Work engaging means on said cam means during movement between said closed position and said open position.

2. The invention as defined in claim 1 and having stop means engageable with said roller means in the closed position.

3. The invention as defined in claim 1 and said work engaging means comprising spaced parallelly extending abutment bars, one end of said bars being adapted to engage the work and the other end of said bars being pivotally connected to said support link means.

4. The invention as defined in claim 3 and having first stop means provided for each of said abutment bars in the closed position.

5. The invention as defined in claim 4 and having second stop means provided on said base means for said support link means in the closed position.

6. The invention as defined in claim 5 and said support link means comprising spaced separate parallel links, each pivoted on each side of said base means at one end and to one of said abut-ment bars at the other end.

7. The invention as defined in claim 1 and wherein said handle means comprises an elongated member extending at substantially right angles to said work engaging means and being pivotally movable relative to said base means to apply force to said work engaging means causing rolling engagement of said roller means along said oam means during movement of said work engaging means between the open position and the closed position.

8. The invention as defined in claim '7 and wherein said cam means includes an abutment portion extending at substantially right angles to the work engaging means in the closed position whereby said roller means is positioned against said abutment portion in the closed position.

9. The invention as defined in claim 6 and said first stop means for said abutment bars and said second stop means for said support link means being located to stop said work engaging means with the pivotal axis at the connection of said control link means to said handle means, the pivotal axis at the connection of said control link means to said work engaging means, and the pivotal axis at the connection of said handle means to said base means being aligned at substantially right angles to said work engaging means.

It The invention as defined in claim 9 and having the axes at said pivotal connection located such that during movement to said open position with said roller means on said cam means, a line drawn through the axis of rotation of said roller means and the pivotal axis of said pivotal connection of said support link means to said work engaging means extends at substantially right angles to a line drawn through the pivotal axis of the connection of said support link means to said base means and the pivotal connection of said control link means to said handle means.

11. A clamp comprising a base, an actuator, support link means, a common pivot connecting said actuator and said support link means to said base, said actuator being movable on said common pivot between clamped and released positions, control link means pivoted to said actuator, work clamping means pivoted to said control link means and to said support link means, means on said base providing a continuous cam surface having an arcuate portion gene-rated about said common pivot and an abutment portion facing away from said arcuate portion, a first roller carried by said work clamping means at the pivot connection thereof with said control link means, a second roller carried by said work clamping means at the pivot connection thereof with said support link means,

and abutment means on said base forming a seat for said support link means when said actuator is in clamped position, both of said rollers adapted to engage and move on the arcuate portion of said cam surface during movement of said actuator on said common pivot and said first roller adapted to move onto the abutment portion of said cam surface when said actuator is in fully clamped position, said rollers bearing on said cam surface and said support link means bearing on said abutment means in the clamped position of said actuator to lock the moving parts of the clamp.

11. The combination as set forth in claim 11 wherein the pivot connection between said actuator and said control link means, the pivot connection between said con trol link means and said work clamping means and said common pivot all move into alignment with each other as the actuator moves to the clamped position and wherein the pivot connection between said control link means and said work clamping means moves over center with respect to the other of said pivot connections as said actuator moves to the fully clamped position.

13. The combination as set forth in claim 11 including abutment means on said control link means engageable with said work clamping means as said actuator moves to the fully clamped position to prevent further movement of said actuator in the clamped direction.

14. The combination as set forth in claim 11 including abutment means on said control link means engageable with said work clamping means as said actuator moves to the released position and operable by such engagement to retract said work clamping means.

15. The combinaiton as set forth in claim 11 including forwardly and rearwardly extending abutment means on said control link means, said forwardly extending abutment means being engageable with said work clamping means as said actuator moves to the fully clamped position and operable by such engagement to limit such movement of said actuator, said rearwardly extending abutment means being engageable with said work clamping means substantially at the pivot connection thereof with said support link means as said actuator moves to the released position and operable by such engagement to retract such work clamping means.

16. The combination as set forth in claim 11 wherein the arcuate portion of said cam surface extends below said common pivot 50 that the operating parts of the clamp are positioned essentially low in the fully released position of said actuator.

17. A toggle clamp having a base, and a movable clamp assembly on said base, said clamp assembly comprising an actuator, support link means, a common pivot connecting said actuator and said support link means to said base, control link means pivoted to said actuator, work clamping means pivoted to said control link means and to said support link means, said actuator being oscillatable on said common pivot to move said work clamping means between clamped and released positions and said control link means forming a toggle connection between said actuator and said work clamping means which straightens in the clamped position of said actuator to hold said Work clamping means against a workpiece engaged thereby, first abutment means on said base engageable by said support link means to limit forward movement of the work clamping means in the clamped position of said :actuator, second abutment means on said base engageable by said control link means as said work clamping means moves to the fully clamped position and operative to hold said support link means solidly against said first abutment means, and means for limiting movement of said actuator toward said work clamping position after said first and said second abutment means have been engage by said support link means and said control link means respectively and after said control link means has straightened in its toggle action against said work clamping means.

18. A toggle clamp having a base, and a movable clamp asse ibly on said base, said clamp assembly comprising an actuator, support link means, a common pivot connecting said actuator and said support link means to said base, control link means pivoted to said actuator, work clamping means pivoted to said control link means and to said support link means, said actuator being rockable forwardly and rearwardly on said common pivot to move said work clamping means between clamped and released positions, rearwardly facing abutment means on said base engageable by said support link means to limit forward movement of the work clamping means in the clamp-ed position, forwardly facing abutment means on said base engageable by said control link means as said work clamping means moves to the fully clamped position to hold said support link means solidly against said first abutment means and for preventing retractive movement of said work clamping means, means for limiting movement of said actuator toward the work clamping position after said abutment means are engaged by said support link means and said control link means, and an arcuate surface on said base generated about said common pivot as a center engageable by and supporting said clamp assembly to guide said work clamping means in its movement between said clamped and said released positions.

19. A toggle clamp having a base, and a movable clamp assembly on said base, said clamp assembly comprising an actuator, support link means, a common pivot connecting said actuator and said support link means to said base, control link means pivoted to said actuator, work clamping means pivoted to said control link means and to said support link means, said actuator adapted to turn on said common pivot to move said work clamping means between clamped and released positions, generally oppositely facing first and second abutment means engageable by said support link means and said control link means respectively as said work clamping means moves to the fully clamped position and operative thereby to hold said work clamping means in the clamped position, and means for limiting movement of said actuator toward the clamped position after engagement of said abutment means by said support and control link means and movement of said work clamping means to the fully clamped position.

20. A toggle clamp having a base, and a movable clamp assembly on said base, said clamp assembly comprising an actuator, support link means, a common pivot connecting said actuator and said support link means to said base, control link means pivoted to said actuator, work clamping means pivoted to said control link means and to said support link means, said actuator adapted to turn on said common pivot to move said work clamping means between clamped and released positions, generally oppositely facing first and second abutment means engageable by said support link means and said control link means respectively as said work clamping means moves to the fully clamped position and operative thereby to hold said Work clamping means in the clamped position, means for limiting movement of said actuator toward the clamped position after engagement of said abutment means by said support and control link means and movement of said work clamping means to the fully clamped position and means on said base for guiding said clamp assembly during movement of said actuator and said work clamping means between said clamped and released positions.

21. A clamp having a base, and a clamp assembly on said base comprising an actuator, support link means, a common pivot connection said actuator and said support link means to said base, said actuator being movable on said common pivot between clamped and released positions, toggle-action control link means pivoted to said actuator, work clamping means pivoted to said control link means and to said support link means, said work 9 10 clamping means being operable to engage and clamp 9. References Cited by the Examiner workpiece as said actuator moves to the fully clamped UNITED STATES PATENTS position and said control link means being movable into alignment With said actuator as the latter moves to tlg 5,436,941 3/1948 Sendoykas 269 '47 fully clamped position, oppositely facing abutment means 5 igggigg g fi on said base engageable by said support link means and 5 5 9/1964 a a 269:228 said control lmk means respectively in the fully clamped 3,204,947 9/1965 sendoykas 269 228 XR position of said actuator and said Work clamping means, and means for limiting movement of said actuator toward WILLIAM DYER, JR, Primary Examiner. the clamped position after said control link means has 10 moved substantially into alignment with said actuator. BRAY Exammw 

1. A CLAMP COMPRISING WORK ENGAGING MEANS MOVABLE BETWEEN AN OPEN RETRACTED POSITION AND A CLOSED CLAMPING POSITION, BASE MEANS MOVABLY SUPPORTING SAID WORK ENGAGING MEANS FOR MOVEMENT BETWEEN THE OPEN POSITION AND THE CLOSED POSITION, SUPPORT LINK MEANS PIVOTALLY CONNECTED TO SAID BASE MEANS AND SAID WORK ENGAGING MEANS, CAM MEANS PROVIDED ON SAID BASE MEANS, HANDLE MEANS PIVOTALLY CONNECTED AT ONE END TO SAID SUPPORT LINK MEANS AND TO SAID BASE MEANS, CONTROL LINK MEANS PIVOTALLY MOUNTED ON SAID HANDLE MEANS AND ON SAID WORK ENGAGING MEANS, FIRST ABUTMENT MEANS FORMED ON SAID CONTROL LINK 